Very Amateur Astronomy

Fixed! All my thanks for this to Bob, my friend and colleague from Basingstoke AS for supplying his time, tools and expertise  to the problem.

This turned out to a be a failed MOSFET on the MC Board (component marked Q2 – Fairchild FDS8449 MOSFET). A trip to a Bob’s, who had the knowledge and required tools to trouble shoot the components quickly identified the failure. Under the microscope the chip was obviously damaged, split slightly along one edge and showing some slight discoloration on two of the pins, not something you would have noticed looking at it unaided.

It was easily replaced, RS Electronics in the UK had the part for £5, and it all appears to be working OK now.

On replacement MC boards, finding one in the UK was proving to be extremely difficult, I did however track one down in Germany through Telescope Service for 129E. So if you are in Europe and find yourself in the same situation I’d suggest checking with them first.

I located one in the US as well at Woodland Hills but they wanted $434 plus shipping, which combined with import tax and duty comes to a quite stupid amount of money.

I was out having a mildly successful evening on Monday night, freezing cold but dark and clear, imaging the Witches Head nebula when all of a sudden my laptop reported a lost connection with the camera and the guiding failed as it lost contact with the mount. Not a good sign.

Out in the shed it quickly became clear that something had gone badly wrong, the regulated power supply which powers the mount, camera and dew heater was still up and running as was the dew heater, but the camera and mount were worryingly devoid of life. I turned everything off at power switches and mains then sequentially brought everything back on, checking first to make sure the PSU wasn’t outputting any weird voltage levels. Thankfully the camera came back up and shows no issues, the mount however remained dead.

Even more unfortunately it is now out of warranty so the simple task of returning it to a dealer is not an option, instead I have to figure out what has died and then source a repair or spare part. Initial investigations show that the motor control board which also contains the power switching components is the point of failure. If powered on while connected to the regulated PSU the output voltage of the PSU drops to around 2.5v, if connected to my leisure battery it instantly blows the mounts fuse.

So the plan of action here is as follows :

1. Ask a friend who knows about these things to take a look at the board, it may just be a failed component which can be replaced, probably one of the two Fairchild PowerTrench MOSFET chips.
2. If that doesn’t work find a UK or EU supplier who can source the board or..
3. Source the board from the US if that turns out to be cheaper (around £250 delivered plus the tax and duty .. ouch)
4. The last option is to find a local dealer or supplier who can carry out a repair, Celestron have linked me to hama who as it happens are right here in Basingstoke which would be handy.

So all very annoying and if the board cannot be repaired by my clever friend then likely to be all very expensive.

In the mean time I will need to move the Sphinx out of it’s between holiday downtime and get it mounted in the shed for widefield work. This will mean making an adapter to mount it on the pier, probably something out of plywood for the time being. I’ve also noticed that the slew rate on the Sphinx is extremely slow, so it may need a quick service to get it back into working order.

This may be the push I need to invest in the NexSXD mod for the Sphinx as well as I have a Nexstar handset from the CGEM. The Starbook is fun but it has never felt that competent compared to the Nexstar, plus it would allow for permanent PEC on the very excellent mechancals of the Sphinx which would be a definite advantage.

That was quicker than expected, I normally leave it for a week or two before starting all over again but this data is actually alright and I wanted to spend more time playing with Normalization and DBE tools.

Anyway, some results, first an attempt to remove the stars as much as possible using star masks and the Morphological Transform tool.

That came out OK I think, though some colour fringing on stars is causing some weird artifacts, I need to spend some more time investigating how to do this.

The second edit is a standard edit just attempting to bring out more of the nebula and control the stars, it’s an improvement I think.

This has been on my target list for quite a while now, and is a favorite imaging target along with it’s partner the Soul Nebula. I have picked up both previously in my widefield image of Cassiopeia and finally got round to doing the heart justice on a couple of evenings in between the clouds last week. Ideally I would like to do a multiframe mosaic with the 250mm reflector but given the lack of clear nights recently I figured I had best stick with a single shot from the ZS66SD for now instead.

• 46 x 300 seconds
• 35 x dark, bias, flat frames
• Canon 1000d (Modified)
• Astronomik CLS-CCD
• William Optics ZS66SD

I will confess to being happy with this image though I still have a few issues which need resolving.

1. Even with the MkII flattener the field still isn’t very flat with bloated stars around the edges.
2. This is made worse by the poor focusser on the ZS66 allowing flop and flex on the draw tube so it’s not centrally aligned with the objectivelens.
3. The background due to light pollution and camera noise mostly is a mess. I need to investigate better ways of managing this with Pixinsight.

Fixing the first item requires either a better flattener or a better telescope entirely, both options I would rather avoid. However sorting out the focusser on the ZS66 would really help, however I have tried sorting it out before and never quite managed to get it much better than it currently is. The last issue needs to be managed by better work with the Background Normalization and DBE tools in Pixinsight, expect a reprocessed version at some point soon as I work that out.

I’ve not forgotten this, really! It’s just been a bit busy of late and the blog has been left on the wayside. I’ll update this weekend with all the recent images, there have been a few.

The quite months and general lack of astrophotography are continuing I’m sorry to say. I did get out to capture a couple of hours worth of data on M101 over the weekend, but as yet I don’t have a finished image to show. Mostly because I dropped the lamp I use to illuminate my white board which is used to take flats, and I keep forgetting to buy a new bulb when I go past a shop. I don’t expect anything great from that data though, it was a windy night and the scopes were getting blown around a bit. Maybe I should look into converting the shed to a turret design at some point.

There is some news though, I submitted some image to the BBC Sky at Night flickr group for the June edition of the show. The theme of the episode is ‘Cygnus the Swan’, so I offered up my Cygnus collection from this time last year, comprising of the North American nebula, the Cygnus Loop, the Crescent Nebula and finally the Gamma Cygni Butterfly.

I am proud to say that at least one of my images was included for inclusion in the show, though I missed Sunday nights edition so I don’t actually know which one the showed! I have Thursday’s extended edition set to record though so I’m looking forward to seeing something I did on the TV.

No new images from me from the last few weeks, even though we did have an  excellent run of clear nights over our two long weekend national holidays. I however was being visited by an old friend not seen for a couple of years and much missed, and spending time with friends and family away from home. I’ll try not to regret the lost imaging time in lieu of how much fun I was having!

The site has had a major update as I have finally got the equipment page up to date with information on my telescopes and mounts. I’ll have further updates on my cameras soon, expect a treatise on the usefulness and general glory of ptfe tape against the evils of unwanted movement.

I made a few modifications over the weekend to the site layout. You’ll notice that the ‘Gallery’ page has gone, and I now have a page each for Messier catalog, NGC & Other Catalogs and Local Objects. Hopefully this is a bit mroe organized now and will be easier to maintain in the future.

I’m not 100% happy at the moment with the layout of the pages, I may change it to use single images, picking the best of each, as on the front page, rather than the click through the gallery as it is right now.

The plan for the weekend if the skies our cloudy is to dismount and photograph the current equipment in order to finally get the equipment page up to date.

A great deal of work went in to producing this six seconds of video. Really, the effect is very neat but it will be worth saving for when the comet is passing something of genuine interest.

So this is Comet Hartley moving against the background stars back in October, 58 frames at 10 frames per second.  Each frame is a single 2 minute exposure captured with my canon 1000D at prime focus on my 250mm reflector.

And a slightly wider view of the same thing, which I quite like because you can see the sky getting darker.

It’s a nice effect, next time I’ll try and get a nice cluster in the field of view and at least twice as many frames.

It’s been nearly a month since I last updated the site, you’d think with a freshly modified camera I’d have been out testing every spare moment and have loads to talk about. Unfortunately the weather as ever, has not been playing ball and the second part of my upgrade project arrived in a large box from Orion Optics a couple of weeks ago so I have been some what busy rebuilding my scope. I’ll put a proper post together hopefully over the weekend on that subject when I have finished the work, lots of lessons learnt there.

I did however manage to make use of a clear and unfortunately moonlit night to take another look at my PEC correction. The last time I did this was back in March and April, when the scope was new and not yet bedded in so it felt like time for another round. I managed to find a gap of 8 worm cycles in between intermittent cloud cover, with the following result :

The peak to peak error there is +14.3/-13.3, which as it happens it pretty much identical to the previous result! So bang goes my ‘bedding in time’ theory, it’s not changed in the slightest. I created a new PEC curve from this data and uploaded it to the mount and got the following result from testing :

So that is +4.7/-4.9 compared to the previous result of +5.5/-5.1, so a little improvement was there to be had. Of course this is a very small change so may be down to better seeing or better alignment. It will be worth testing this result another day I think and seeing if I am able to better it.